/**
 * @file
 *
 * @ingroup bsp_interrupt
 *
 * @brief Header file for generic BSP interrupt support.
 */

/*
 * Based on concepts of Pavel Pisa, Till Straumann and Eric Valette. 
 *
 * Copyright (c) 2008
 * Embedded Brains GmbH
 * Obere Lagerstr. 30
 * D-82178 Puchheim
 * Germany
 * rtems@embedded-brains.de
 *
 * The license and distribution terms for this file may be found in the file
 * LICENSE in this distribution or at http://www.rtems.com/license/LICENSE.
 */

#ifndef LIBBSP_SHARED_IRQ_GENERIC_H
#define LIBBSP_SHARED_IRQ_GENERIC_H

#include <stdbool.h>

#include <rtems/irq-extension.h>

#include <bsp/irq-config.h>

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

#if !defined( BSP_INTERRUPT_VECTOR_MIN) || !defined( BSP_INTERRUPT_VECTOR_MAX) || (BSP_INTERRUPT_VECTOR_MAX + 1) < BSP_INTERRUPT_VECTOR_MIN
#error Invalid BSP_INTERRUPT_VECTOR_MIN or BSP_INTERRUPT_VECTOR_MAX.
#endif /* !defined( BSP_INTERRUPT_VECTOR_MIN) ... */

#if defined( BSP_INTERRUPT_USE_INDEX_TABLE) && !defined( BSP_INTERRUPT_HANDLER_TABLE_SIZE)
#error If you define BSP_INTERRUPT_USE_INDEX_TABLE, you have to define BSP_INTERRUPT_HANDLER_TABLE_SIZE etc. as well.
#endif /* defined( BSP_INTERRUPT_USE_INDEX_TABLE) ... */

#if defined( BSP_INTERRUPT_NO_HEAP_USAGE) && !defined( BSP_INTERRUPT_USE_INDEX_TABLE)
#error If you define BSP_INTERRUPT_NO_HEAP_USAGE, you have to define BSP_INTERRUPT_USE_INDEX_TABLE etc. as well.
#endif /* defined( BSP_INTERRUPT_NO_HEAP_USAGE) ... */

#define BSP_INTERRUPT_VECTOR_NUMBER (BSP_INTERRUPT_VECTOR_MAX - BSP_INTERRUPT_VECTOR_MIN + 1)

#ifndef BSP_INTERRUPT_HANDLER_TABLE_SIZE
#define BSP_INTERRUPT_HANDLER_TABLE_SIZE BSP_INTERRUPT_VECTOR_NUMBER
#endif /* BSP_INTERRUPT_HANDLER_TABLE_SIZE */

struct bsp_interrupt_handler_entry {
	rtems_interrupt_handler handler;
	void *arg;
	const char *info;
	struct bsp_interrupt_handler_entry *next;
};

typedef struct bsp_interrupt_handler_entry bsp_interrupt_handler_entry;

extern bsp_interrupt_handler_entry bsp_interrupt_handler_table [];

#ifdef BSP_INTERRUPT_USE_INDEX_TABLE
extern bsp_interrupt_handler_index_type bsp_interrupt_handler_index_table [];
#endif /* BSP_INTERRUPT_USE_INDEX_TABLE */

static inline rtems_vector_number bsp_interrupt_handler_index( rtems_vector_number vector)
{
#ifdef BSP_INTERRUPT_USE_INDEX_TABLE
	return bsp_interrupt_handler_index_table [vector - BSP_INTERRUPT_VECTOR_MIN];
#else /* BSP_INTERRUPT_USE_INDEX_TABLE */
	return vector - BSP_INTERRUPT_VECTOR_MIN;
#endif /* BSP_INTERRUPT_USE_INDEX_TABLE */
}

void bsp_interrupt_handler_empty( rtems_vector_number vector, void *arg);

static inline bool bsp_interrupt_is_empty_handler_entry( bsp_interrupt_handler_entry *e)
{
	return e->handler == bsp_interrupt_handler_empty;
}

/**
 * @defgroup bsp_interrupt BSP Interrupt Support
 *
 * @ingroup rtems_interrupt_extension
 *
 * The BSP interrupt support manages a sequence of interrupt vector numbers
 * ranging from @ref BSP_INTERRUPT_VECTOR_MIN to @ref BSP_INTERRUPT_VECTOR_MAX
 * including the end points.  It provides methods to @ref
 * bsp_interrupt_handler_install() "install", @ref
 * bsp_interrupt_handler_remove() "remove" and @ref
 * bsp_interrupt_handler_dispatch() "dispatch" interrupt handlers for each
 * vector number.  It implements parts of the RTEMS interrupt manager.
 *
 * The entry points to a list of interrupt handlers are stored in a table
 * (= handler table).
 *
 * You have to configure the BSP interrupt support in the bsp/irq-config.h file
 * for each BSP.  For a minimum configuration you have to provide @ref
 * BSP_INTERRUPT_VECTOR_MIN and @ref BSP_INTERRUPT_VECTOR_MAX.
 *
 * For boards with small memory requirements you can define @ref
 * BSP_INTERRUPT_USE_INDEX_TABLE.  With an enabled index table the handler
 * table will be accessed via a small index table.  You can define the size of
 * the handler table with @ref BSP_INTERRUPT_HANDLER_TABLE_SIZE.  You must
 * provide a data type for the index table (@ref
 * bsp_interrupt_handler_index_type).  It must be an integer type big enough to
 * index the complete handler table.
 *
 * Normally new list entries are allocated from the heap.  You may define @ref
 * BSP_INTERRUPT_NO_HEAP_USAGE, if you do not want to use the heap.  For this
 * option you have to define @ref BSP_INTERRUPT_USE_INDEX_TABLE as well.
 *
 * You have to provide some special routines in your BSP (follow the links for
 * the details):
 * - bsp_interrupt_facility_initialize()
 * - bsp_interrupt_vector_enable()
 * - bsp_interrupt_vector_disable()
 * - bsp_interrupt_handler_default()
 *
 * The following now deprecated functions are provided for backward
 * compatibility:
 * - BSP_get_current_rtems_irq_handler()
 * - BSP_install_rtems_irq_handler()
 * - BSP_install_rtems_shared_irq_handler()
 * - BSP_remove_rtems_irq_handler()
 * - BSP_rtems_irq_mngt_set()
 * - BSP_rtems_irq_mngt_get()
 *
 * @{
 */

/**
 * @brief Returns true if the interrupt vector with number @a vector is valid.
 */
static inline bool bsp_interrupt_is_valid_vector( rtems_vector_number vector)
{
	return (rtems_vector_number) BSP_INTERRUPT_VECTOR_MIN <= vector
		&& vector <= (rtems_vector_number) BSP_INTERRUPT_VECTOR_MAX;
}

/**
 * @brief Default interrupt handler.
 *
 * This routine will be called from bsp_interrupt_handler_dispatch() with the
 * current vector number @a vector when the handler list for this vector is
 * empty or the vector number is out of range.
 *
 * @note This function must cope with arbitrary vector numbers @a vector.
 */
void bsp_interrupt_handler_default( rtems_vector_number vector);

rtems_status_code bsp_interrupt_initialize();

/**
 * @brief BSP specific initialization.
 *
 * This routine will be called form bsp_interrupt_initialize() and shall do the
 * following:
 * - Initialize the facilities that call bsp_interrupt_handler_dispatch().  For
 * example on PowerPC the external exception handler.
 * - Initialize the interrupt controller.  You shall set the interrupt
 * controller in a state such that interrupts are disabled for all vectors.
 * The vectors will be enabled with your bsp_interrupt_vector_enable() function
 * and disabled via your bsp_interrupt_vector_disable() function.  These
 * functions have to work afterwards.
 *
 * @return On success RTEMS_SUCCESSFUL shall be returned.
 */
rtems_status_code bsp_interrupt_facility_initialize();

/**
 * @brief Enables the interrupt vector with number @a vector.
 *
 * This function shall enable the vector at the corresponding facility (in most
 * cases the interrupt controller).  It will be called then the first handler
 * is installed for the vector in bsp_interrupt_handler_install().  For a
 * vector out of range this function shall do nothing except returning
 * RTEMS_SUCCESSFUL.
 *
 * @note You must not install or remove an interrupt handler in this function.
 * This may result in a deadlock.
 *
 * @return On success RTEMS_SUCCESSFUL shall be returned.
 */
rtems_status_code bsp_interrupt_vector_enable( rtems_vector_number vector);

/**
 * @brief Disables the interrupt vector with number @a vector.
 *
 * This function shall disable the vector at the corresponding facility (in
 * most cases the interrupt controller).  It will be called then the last
 * handler is removed for the vector in bsp_interrupt_handler_remove().  For a
 * vector out of range this function shall do nothing except returning
 * RTEMS_SUCCESSFUL.
 *
 * @note You must not install or remove an interrupt handler in this function.
 * This may result in a deadlock.
 *
 * @return On success RTEMS_SUCCESSFUL shall be returned.
 */
rtems_status_code bsp_interrupt_vector_disable( rtems_vector_number vector);

/**
 * @brief Sequencially calls all interrupt handlers for the vector number @a
 * vector.
 *
 * If the vector number is out of range or the handler list is empty
 * bsp_interrupt_handler_default() will be called with argument @a vector.
 *
 * You can call this function within every context which can be disabled via
 * rtems_interrupt_disable().
 */
static inline void bsp_interrupt_handler_dispatch( rtems_vector_number vector)
{
	if (bsp_interrupt_is_valid_vector( vector)) {
		bsp_interrupt_handler_entry *head = &bsp_interrupt_handler_table [bsp_interrupt_handler_index( vector)];
		bsp_interrupt_handler_entry *current = head;

		do {
			current->handler( vector, current->arg);
			current = current->next;
		} while (current != NULL);

		if (bsp_interrupt_is_empty_handler_entry( head)) {
			bsp_interrupt_handler_default( vector);
		}
	} else {
		bsp_interrupt_handler_default( vector);
	}
}

/** @} */

#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif /* LIBBSP_SHARED_IRQ_GENERIC_H */
